update vendor

.gitignore

@@ -0,0 +1 @@
+examples/

.travis.yml

@@ -1,3 +1,3 @@
 language: go
 go:
-  - "1.12.5"
+  - "1.14"

LICENSE.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 Artem Piskun
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -4,6 +4,8 @@
 
 go-discogs is a Go client library for the [Discogs API](https://www.discogs.com/developers/). Check the usage section to see how to access the Discogs API.
 
+The lib is under MIT but be sure you are familiar with [Discogs API Terms of Use](https://support.discogs.com/hc/en-us/articles/360009334593-API-Terms-of-Use).
+
 ### Feauteres
  * Database
   * [Releases](#releases)
@@ -18,7 +20,7 @@ go-discogs is a Go client library for the [Discogs API](https://www.discogs.com/
  
 Install
 --------
-    go get -u github.com/irlndts/go-discogs
+    go get github.com/irlndts/go-discogs
 
 Usage
 ---------
@@ -29,18 +31,19 @@ import "github.com/irlndts/go-discogs"
 ```
 
 Some requests require authentification (as any user). According to [Discogs](https://www.discogs.com/developers/#page:authentication,header:authentication-discogs-auth-flow), to send requests with Discogs Auth, you have two options: sending your credentials in the query string with key and secret parameters or a [token parameter](https://www.discogs.com/settings/developers).
-This is token way example:
+
 ```go
-client, err := discogs.NewClient(&discogs.Options{
+client, err := discogs.New(&discogs.Options{
         UserAgent: "Some Name",
         Currency:  "EUR", // optional, "USD" (default), "GBP", "EUR", "CAD", "AUD", "JPY", "CHF", "MXN", "BRL", "NZD", "SEK", "ZAR" are allowed
         Token:     "Some Token", // optional
+        URL:       "https://api.discogs.com", // optional
     })
 ``` 
 
 #### Releases
 ```go
-  release, _ := client.Database.Release(9893847)
+  release, _ := client.Release(9893847)
   fmt.Println(release.Artists[0].Name, " - ", release.Title) 
   // St. Petersburg Ska-Jazz Review  -  Elephant Riddim
 ```
@@ -72,18 +75,16 @@ type SearchRequest struct {
     Contributer   string // search contributor usernames (optional)
 
     Page     int // optional
-    PerPage int // optional
+    PerPage  int // optional
 }
 ```
 
 Example
 ```go
   request := discogs.SearchRequest{Artist: "reggaenauts", ReleaseTitle: "river rock", Page: 0, PerPage: 1}
-  search, _ := client.Search.Search(request)
+  search, _ := client.Search(request)
 
   for _, r := range search.Results {
     fmt.Println(r.Title)
   }
 ```
-
-etc. 

database.go

@@ -12,20 +12,39 @@ const (
 	mastersURI  = "/masters/"
 )
 
-// DatabaseService ...
+// DatabaseService is an interface to work with database.
-type DatabaseService struct {
+type DatabaseService interface {
+	// Artist represents a person in the discogs database.
+	Artist(artistID int) (*Artist, error)
+	// ArtistReleases returns a list of releases and masters associated with the artist.
+	ArtistReleases(artistID int, pagination *Pagination) (*ArtistReleases, error)
+	// Label returns a label.
+	Label(labelID int) (*Label, error)
+	// LabelReleases returns a list of Releases associated with the label.
+	LabelReleases(labelID int, pagination *Pagination) (*LabelReleases, error)
+	// Master returns a master release.
+	Master(masterID int) (*Master, error)
+	// MasterVersions retrieves a list of all Releases that are versions of this master.
+	MasterVersions(masterID int, pagination *Pagination) (*MasterVersions, error)
+	// Release returns release by release's ID.
+	Release(releaseID int) (*Release, error)
+	// ReleaseRating retruns community release rating.
+	ReleaseRating(releaseID int) (*ReleaseRating, error)
+}
+
+type databaseService struct {
 	url      string
 	currency string
 }
 
-func newDatabaseService(url string, currency string) *DatabaseService {
+func newDatabaseService(url string, currency string) DatabaseService {
-	return &DatabaseService{
+	return &databaseService{
 		url:      url,
 		currency: currency,
 	}
 }
 
-// Release serves relesase response from discogs
+// Release serves relesase response from discogs.
 type Release struct {
 	Title             string         `json:"title"`
 	ID                int            `json:"id"`
@@ -54,7 +73,7 @@ type Release struct {
 	Released          string         `json:"released"`
 	ReleasedFormatted string         `json:"released_formatted"`
 	ResourceURL       string         `json:"resource_url"`
-	Series            []string       `json:"series"`
+	Series            []Series       `json:"series"`
 	Status            string         `json:"status"`
 	Styles            []string       `json:"styles"`
 	Tracklist         []Track        `json:"tracklist"`
@@ -63,8 +82,7 @@ type Release struct {
 	Year              int            `json:"year"`
 }
 
-// Release returns release by release's ID
+func (s *databaseService) Release(releaseID int) (*Release, error) {
-func (s *DatabaseService) Release(releaseID int) (*Release, error) {
 	params := url.Values{}
 	params.Set("curr_abbr", s.currency)
 
@@ -73,14 +91,13 @@ func (s *DatabaseService) Release(releaseID int) (*Release, error) {
 	return release, err
 }
 
-// ReleaseRating serves response for community release rating request
+// ReleaseRating serves response for community release rating request.
 type ReleaseRating struct {
 	ID     int    `json:"release_id"`
 	Rating Rating `json:"rating"`
 }
 
-// ReleaseRating retruns community release rating
+func (s *databaseService) ReleaseRating(releaseID int) (*ReleaseRating, error) {
-func (s *DatabaseService) ReleaseRating(releaseID int) (*ReleaseRating, error) {
 	var rating *ReleaseRating
 	err := request(s.url+releasesURI+strconv.Itoa(releaseID)+"/rating", nil, &rating)
 	return rating, err
@@ -105,8 +122,7 @@ type Artist struct {
 	DataQuality    string   `json:"data_quality"`
 }
 
-// Artist represents a person in the discogs database
+func (s *databaseService) Artist(artistID int) (*Artist, error) {
-func (s *DatabaseService) Artist(artistID int) (*Artist, error) {
 	var artist *Artist
 	err := request(s.url+artistsURI+strconv.Itoa(artistID), nil, &artist)
 	return artist, err
@@ -118,8 +134,7 @@ type ArtistReleases struct {
 	Releases   []ReleaseSource `json:"releases"`
 }
 
-// ArtistReleases returns a list of releases and masters associated with the artist.
+func (s *databaseService) ArtistReleases(artistID int, pagination *Pagination) (*ArtistReleases, error) {
-func (s *DatabaseService) ArtistReleases(artistID int, pagination *Pagination) (*ArtistReleases, error) {
 	var releases *ArtistReleases
 	err := request(s.url+artistsURI+strconv.Itoa(artistID)+"/releases", pagination.params(), &releases)
 	return releases, err
@@ -141,8 +156,7 @@ type Label struct {
 	DataQuality string     `json:"data_quality"`
 }
 
-// Label returns a label.
+func (s *databaseService) Label(labelID int) (*Label, error) {
-func (s *DatabaseService) Label(labelID int) (*Label, error) {
 	var label *Label
 	err := request(s.url+labelsURI+strconv.Itoa(labelID), nil, &label)
 	return label, err
@@ -154,8 +168,7 @@ type LabelReleases struct {
 	Releases   []ReleaseSource `json:"releases"`
 }
 
-// LabelReleases returns a list of Releases associated with the label.
+func (s *databaseService) LabelReleases(labelID int, pagination *Pagination) (*LabelReleases, error) {
-func (s *DatabaseService) LabelReleases(labelID int, pagination *Pagination) (*LabelReleases, error) {
 	var releases *LabelReleases
 	err := request(s.url+labelsURI+strconv.Itoa(labelID)+"/releases", pagination.params(), &releases)
 	return releases, err
@@ -187,8 +200,7 @@ type Master struct {
 	DataQuality          string         `json:"data_quality"`
 }
 
-// Master returns a master release
+func (s *databaseService) Master(masterID int) (*Master, error) {
-func (s *DatabaseService) Master(masterID int) (*Master, error) {
 	var master *Master
 	err := request(s.url+mastersURI+strconv.Itoa(masterID), nil, &master)
 	return master, err
@@ -200,8 +212,7 @@ type MasterVersions struct {
 	Versions   []Version `json:"versions"`
 }
 
-// MasterVersions retrieves a list of all Releases that are versions of this master
+func (s *databaseService) MasterVersions(masterID int, pagination *Pagination) (*MasterVersions, error) {
-func (s *DatabaseService) MasterVersions(masterID int, pagination *Pagination) (*MasterVersions, error) {
 	var versions *MasterVersions
 	err := request(s.url+mastersURI+strconv.Itoa(masterID)+"/versions", pagination.params(), &versions)
 	return versions, err

database_test.go

@@ -60,7 +60,7 @@ func TestDatabaseServiceRelease(t *testing.T) {
 	defer ts.Close()
 
 	d := initDiscogsClient(t, &Options{URL: ts.URL})
-	release, err := d.Database.Release(8138518)
+	release, err := d.Release(8138518)
 	if err != nil {
 		t.Fatalf("failed to get release: %s", err)
 	}
@@ -78,7 +78,7 @@ func TestDatabaseServiceMaster(t *testing.T) {
 	defer ts.Close()
 
 	d := initDiscogsClient(t, &Options{URL: ts.URL})
-	master, err := d.Database.Master(718441)
+	master, err := d.Master(718441)
 	if err != nil {
 		t.Fatalf("failed to get master: %s", err)
 	}
@@ -95,7 +95,7 @@ func TestDatabaseServiceArtist(t *testing.T) {
 	defer ts.Close()
 
 	d := initDiscogsClient(t, &Options{URL: ts.URL})
-	artist, err := d.Database.Artist(38661)
+	artist, err := d.Artist(38661)
 	if err != nil {
 		t.Fatalf("failed to get master: %s", err)
 	}

discogs.go

@@ -14,22 +14,31 @@ const (
 
 // Options is a set of options to use discogs API client
 type Options struct {
-	URL       string
+	// Discogs API endpoint (optional).
-	Currency  string
+	URL string
+	// Currency to use (optional, default is USD).
+	Currency string
+	// UserAgent to to call discogs api with.
 	UserAgent string
-	Token     string
+	// Token provided by discogs (optional).
+	Token string
 }
 
-// Client is a Discogs client for making Discogs API requests.
+// Discogs is an interface for making Discogs API requests.
-type Client struct {
+type Discogs interface {
-	Database *DatabaseService
+	DatabaseService
-	Search   *SearchService
+	SearchService
+}
+
+type discogs struct {
+	DatabaseService
+	SearchService
 }
 
 var header *http.Header
 
-// NewClient returns a new Client.
+// New returns a new discogs API client.
-func NewClient(o *Options) (*Client, error) {
+func New(o *Options) (Discogs, error) {
 	header = &http.Header{}
 
 	if o == nil || o.UserAgent == "" {
@@ -52,9 +61,9 @@ func NewClient(o *Options) (*Client, error) {
 		o.URL = discogsAPI
 	}
 
-	return &Client{
+	return discogs{
-		Database: newDatabaseService(o.URL, cur),
+		newDatabaseService(o.URL, cur),
-		Search:   newSearchService(o.URL + "/database/search"),
+		newSearchService(o.URL + "/database/search"),
 	}, nil
 }
 

discogs_test.go

@@ -5,11 +5,11 @@ import (
 )
 
 const (
-	testUserAgent = "UnitTestClient/0.0.2 +https://github.com/irlndts/go-discogs"
+	testUserAgent = "UnitTestClient/0.0.2"
 	testToken     = ""
 )
 
-func initDiscogsClient(t *testing.T, options *Options) *Client {
+func initDiscogsClient(t *testing.T, options *Options) Discogs {
 	if options == nil {
 		options = &Options{
 			UserAgent: testUserAgent,
@@ -22,7 +22,7 @@ func initDiscogsClient(t *testing.T, options *Options) *Client {
 		options.UserAgent = testUserAgent
 	}
 
-	client, err := NewClient(options)
+	client, err := New(options)
 	if err != nil {
 		t.Fatalf("failed to create client: %s", err)
 	}
@@ -30,7 +30,7 @@ func initDiscogsClient(t *testing.T, options *Options) *Client {
 	return client
 }
 
-func TestNewClient(t *testing.T) {
+func TestNew(t *testing.T) {
 	tests := map[string]struct {
 		options *Options
 		err     error
@@ -53,7 +53,7 @@ func TestNewClient(t *testing.T) {
 	for name := range tests {
 		tt := tests[name]
 		t.Run(name, func(t *testing.T) {
-			if _, err := NewClient(tt.options); err != tt.err {
+			if _, err := New(tt.options); err != tt.err {
 				t.Errorf("err got=%s; want=%s", err, tt.err)
 			}
 		})
@@ -66,19 +66,19 @@ func TestCurrency(t *testing.T) {
 		want     string
 		err      error
 	}{
-		{currency: "", want: "USD", err: nil},
+		{currency: "", want: "USD"},
-		{currency: "USD", want: "USD", err: nil},
+		{currency: "USD", want: "USD"},
-		{currency: "GBP", want: "GBP", err: nil},
+		{currency: "GBP", want: "GBP"},
-		{currency: "EUR", want: "EUR", err: nil},
+		{currency: "EUR", want: "EUR"},
-		{currency: "CAD", want: "CAD", err: nil},
+		{currency: "CAD", want: "CAD"},
-		{currency: "AUD", want: "AUD", err: nil},
+		{currency: "AUD", want: "AUD"},
-		{currency: "JPY", want: "JPY", err: nil},
+		{currency: "JPY", want: "JPY"},
-		{currency: "CHF", want: "CHF", err: nil},
+		{currency: "CHF", want: "CHF"},
-		{currency: "MXN", want: "MXN", err: nil},
+		{currency: "MXN", want: "MXN"},
-		{currency: "BRL", want: "BRL", err: nil},
+		{currency: "BRL", want: "BRL"},
-		{currency: "NZD", want: "NZD", err: nil},
+		{currency: "NZD", want: "NZD"},
-		{currency: "SEK", want: "SEK", err: nil},
+		{currency: "SEK", want: "SEK"},
-		{currency: "ZAR", want: "ZAR", err: nil},
+		{currency: "ZAR", want: "ZAR"},
 		{currency: "RUR", want: "", err: ErrCurrencyNotSupported},
 	}
 	for i, tt := range tests {

doc.go

@@ -0,0 +1,21 @@
+/*
+Package discogs is a Go client library for the Discogs API.
+
+The discogs package provides a client for accessing the Discogs API.
+First of all import library and init client variable.
+According to discogs api documentation you must provide your user-agent.
+
+Some requests require authentification (as any user).
+According to Discogs, to send requests with Discogs Auth, you have two options:
+sending your credentials in the query string with key and secret parameters or
+a token parameter. This is token way example:
+
+	client, err := discogs.New(&discogs.Options{
+		UserAgent: "Some Name",
+		Currency:  "EUR", // optional, "USD" (default), "GBP", "EUR", "CAD", "AUD", "JPY", "CHF", "MXN", "BRL", "NZD", "SEK", "ZAR" are allowed
+		Token:     "Some Token", // optional
+		URL:       "https://api.discogs.com", // optional
+	})
+
+*/
+package discogs

examples/discogs_example.go

@@ -1,26 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	"github.com/irlndts/go-discogs"
-)
-
-func main() {
-	d, err := discogs.NewClient(&discogs.Options{
-		UserAgent: "TestDiscogsClient/0.0.1 +http://example.com",
-		Currency:  "USD",
-		Token:     "",
-	})
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-
-	master, err := d.Database.Master(718441)
-	if err != nil {
-		fmt.Println(err)
-		return
-	}
-	fmt.Printf("%+v\n", master)
-}

go.mod

@@ -1,5 +1,5 @@
 module github.com/irlndts/go-discogs
 
-go 1.13.4
+go 1.14
 
-require github.com/google/go-cmp v0.3.1
+require github.com/google/go-cmp v0.4.1

go.sum

@@ -1,2 +1,4 @@
-github.com/google/go-cmp v0.3.1 h1:Xye71clBPdm5HgqGwUkwhbynsUJZhDbS20FvLhQ2izg=
+github.com/google/go-cmp v0.4.1 h1:/exdXoGamhu5ONeUJH0deniYLWYvQwW66yvlfiiKTu0=
-github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/google/go-cmp v0.4.1/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

models.go

@@ -14,6 +14,17 @@ type Video struct {
 	URI         string `json:"uri"`
 }
 
+// Series ...
+type Series struct {
+	Catno          string `json:"catno"`
+	EntityType     string `json:"entity_type"`
+	EntityTypeName string `json:"entity_type_name"`
+	ID             int    `json:"id"`
+	Name           string `json:"name"`
+	ResourceURL    string `json:"resource_url"`
+	ThumbnailURL   string `json:"thumbnail_url,omitempty"`
+}
+
 // ArtistSource ...
 type ArtistSource struct {
 	Anv         string `json:"anv"`
@@ -57,8 +68,9 @@ type LabelSource struct {
 
 // Identifier ...
 type Identifier struct {
-	Type  string `json:"type"`
+	Description string `json:"description,omitempty"`
-	Value string `json:"value"`
+	Type        string `json:"type"`
+	Value       string `json:"value"`
 }
 
 // Format ...

search.go

@@ -5,13 +5,22 @@ import (
 	"strconv"
 )
 
-// SearchService ...
+// SearchService is an interface to work with search.
-type SearchService struct {
+type SearchService interface {
+	// Search makes search request to discogs.
+	// Issue a search query to database. This endpoint accepts pagination parameters.
+	// Authentication (as any user) is required.
+	// https://www.discogs.com/developers/#page:database,header:database-search
+	Search(req SearchRequest) (*Search, error)
+}
+
+// searchService ...
+type searchService struct {
 	url string
 }
 
-func newSearchService(url string) *SearchService {
+func newSearchService(url string) SearchService {
-	return &SearchService{
+	return &searchService{
 		url: url,
 	}
 }
@@ -136,11 +145,7 @@ type Result struct {
 	MasterID    int       `json:"master_id,omitempty"`
 }
 
-// Search makes search request to discogs.
+func (s *searchService) Search(req SearchRequest) (*Search, error) {
-// Issue a search query to our database. This endpoint accepts pagination parameters.
-// Authentication (as any user) is required.
-// https://www.discogs.com/developers/#page:database,header:database-search
-func (s *SearchService) Search(req SearchRequest) (*Search, error) {
 	var search *Search
 	err := request(s.url, req.params(), &search)
 	return search, err

vendor/github.com/google/go-cmp/cmp/compare.go

@@ -6,6 +6,10 @@
 //
 // This package is intended to be a more powerful and safer alternative to
 // reflect.DeepEqual for comparing whether two values are semantically equal.
+// It is intended to only be used in tests, as performance is not a goal and
+// it may panic if it cannot compare the values. Its propensity towards
+// panicking means that its unsuitable for production environments where a
+// spurious panic may be fatal.
 //
 // The primary features of cmp are:
 //
@@ -22,8 +26,8 @@
 // equality is determined by recursively comparing the primitive kinds on both
 // values, much like reflect.DeepEqual. Unlike reflect.DeepEqual, unexported
 // fields are not compared by default; they result in panics unless suppressed
-// by using an Ignore option (see cmpopts.IgnoreUnexported) or explicitly compared
+// by using an Ignore option (see cmpopts.IgnoreUnexported) or explicitly
-// using the AllowUnexported option.
+// compared using the Exporter option.
 package cmp
 
 import (
@@ -62,8 +66,8 @@ import (
 //
 // Structs are equal if recursively calling Equal on all fields report equal.
 // If a struct contains unexported fields, Equal panics unless an Ignore option
-// (e.g., cmpopts.IgnoreUnexported) ignores that field or the AllowUnexported
+// (e.g., cmpopts.IgnoreUnexported) ignores that field or the Exporter option
-// option explicitly permits comparing the unexported field.
+// explicitly permits comparing the unexported field.
 //
 // Slices are equal if they are both nil or both non-nil, where recursively
 // calling Equal on all non-ignored slice or array elements report equal.
@@ -80,6 +84,11 @@ import (
 // Pointers and interfaces are equal if they are both nil or both non-nil,
 // where they have the same underlying concrete type and recursively
 // calling Equal on the underlying values reports equal.
+//
+// Before recursing into a pointer, slice element, or map, the current path
+// is checked to detect whether the address has already been visited.
+// If there is a cycle, then the pointed at values are considered equal
+// only if both addresses were previously visited in the same path step.
 func Equal(x, y interface{}, opts ...Option) bool {
 	vx := reflect.ValueOf(x)
 	vy := reflect.ValueOf(y)
@@ -137,6 +146,7 @@ type state struct {
 	// Calling statelessCompare must not result in observable changes to these.
 	result    diff.Result // The current result of comparison
 	curPath   Path        // The current path in the value tree
+	curPtrs   pointerPath // The current set of visited pointers
 	reporters []reporter  // Optional reporters
 
 	// recChecker checks for infinite cycles applying the same set of
@@ -148,13 +158,14 @@ type state struct {
 	dynChecker dynChecker
 
 	// These fields, once set by processOption, will not change.
-	exporters map[reflect.Type]bool // Set of structs with unexported field visibility
+	exporters []exporter // List of exporters for structs with unexported fields
-	opts      Options               // List of all fundamental and filter options
+	opts      Options    // List of all fundamental and filter options
 }
 
 func newState(opts []Option) *state {
 	// Always ensure a validator option exists to validate the inputs.
 	s := &state{opts: Options{validator{}}}
+	s.curPtrs.Init()
 	s.processOption(Options(opts))
 	return s
 }
@@ -174,13 +185,8 @@ func (s *state) processOption(opt Option) {
 			panic(fmt.Sprintf("cannot use an unfiltered option: %v", opt))
 		}
 		s.opts = append(s.opts, opt)
-	case visibleStructs:
+	case exporter:
-		if s.exporters == nil {
+		s.exporters = append(s.exporters, opt)
-			s.exporters = make(map[reflect.Type]bool)
-		}
-		for t := range opt {
-			s.exporters[t] = true
-		}
 	case reporter:
 		s.reporters = append(s.reporters, opt)
 	default:
@@ -192,9 +198,9 @@ func (s *state) processOption(opt Option) {
 // This function is stateless in that it does not alter the current result,
 // or output to any registered reporters.
 func (s *state) statelessCompare(step PathStep) diff.Result {
-	// We do not save and restore the curPath because all of the compareX
+	// We do not save and restore curPath and curPtrs because all of the
-	// methods should properly push and pop from the path.
+	// compareX methods should properly push and pop from them.
-	// It is an implementation bug if the contents of curPath differs from
+	// It is an implementation bug if the contents of the paths differ from
 	// when calling this function to when returning from it.
 
 	oldResult, oldReporters := s.result, s.reporters
@@ -216,9 +222,17 @@ func (s *state) compareAny(step PathStep) {
 	}
 	s.recChecker.Check(s.curPath)
 
-	// Obtain the current type and values.
+	// Cycle-detection for slice elements (see NOTE in compareSlice).
 	t := step.Type()
 	vx, vy := step.Values()
+	if si, ok := step.(SliceIndex); ok && si.isSlice && vx.IsValid() && vy.IsValid() {
+		px, py := vx.Addr(), vy.Addr()
+		if eq, visited := s.curPtrs.Push(px, py); visited {
+			s.report(eq, reportByCycle)
+			return
+		}
+		defer s.curPtrs.Pop(px, py)
+	}
 
 	// Rule 1: Check whether an option applies on this node in the value tree.
 	if s.tryOptions(t, vx, vy) {
@@ -354,6 +368,7 @@ func sanitizeValue(v reflect.Value, t reflect.Type) reflect.Value {
 func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) {
 	var vax, vay reflect.Value // Addressable versions of vx and vy
 
+	var mayForce, mayForceInit bool
 	step := StructField{&structField{}}
 	for i := 0; i < t.NumField(); i++ {
 		step.typ = t.Field(i).Type
@@ -375,7 +390,13 @@ func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) {
 				vax = makeAddressable(vx)
 				vay = makeAddressable(vy)
 			}
-			step.mayForce = s.exporters[t]
+			if !mayForceInit {
+				for _, xf := range s.exporters {
+					mayForce = mayForce || xf(t)
+				}
+				mayForceInit = true
+			}
+			step.mayForce = mayForce
 			step.pvx = vax
 			step.pvy = vay
 			step.field = t.Field(i)
@@ -391,9 +412,21 @@ func (s *state) compareSlice(t reflect.Type, vx, vy reflect.Value) {
 		return
 	}
 
-	// TODO: Support cyclic data structures.
+	// NOTE: It is incorrect to call curPtrs.Push on the slice header pointer
+	// since slices represents a list of pointers, rather than a single pointer.
+	// The pointer checking logic must be handled on a per-element basis
+	// in compareAny.
+	//
+	// A slice header (see reflect.SliceHeader) in Go is a tuple of a starting
+	// pointer P, a length N, and a capacity C. Supposing each slice element has
+	// a memory size of M, then the slice is equivalent to the list of pointers:
+	//	[P+i*M for i in range(N)]
+	//
+	// For example, v[:0] and v[:1] are slices with the same starting pointer,
+	// but they are clearly different values. Using the slice pointer alone
+	// violates the assumption that equal pointers implies equal values.
 
-	step := SliceIndex{&sliceIndex{pathStep: pathStep{typ: t.Elem()}}}
+	step := SliceIndex{&sliceIndex{pathStep: pathStep{typ: t.Elem()}, isSlice: isSlice}}
 	withIndexes := func(ix, iy int) SliceIndex {
 		if ix >= 0 {
 			step.vx, step.xkey = vx.Index(ix), ix
@@ -470,7 +503,12 @@ func (s *state) compareMap(t reflect.Type, vx, vy reflect.Value) {
 		return
 	}
 
-	// TODO: Support cyclic data structures.
+	// Cycle-detection for maps.
+	if eq, visited := s.curPtrs.Push(vx, vy); visited {
+		s.report(eq, reportByCycle)
+		return
+	}
+	defer s.curPtrs.Pop(vx, vy)
 
 	// We combine and sort the two map keys so that we can perform the
 	// comparisons in a deterministic order.
@@ -507,7 +545,12 @@ func (s *state) comparePtr(t reflect.Type, vx, vy reflect.Value) {
 		return
 	}
 
-	// TODO: Support cyclic data structures.
+	// Cycle-detection for pointers.
+	if eq, visited := s.curPtrs.Push(vx, vy); visited {
+		s.report(eq, reportByCycle)
+		return
+	}
+	defer s.curPtrs.Pop(vx, vy)
 
 	vx, vy = vx.Elem(), vy.Elem()
 	s.compareAny(Indirect{&indirect{pathStep{t.Elem(), vx, vy}}})

vendor/github.com/google/go-cmp/cmp/export_panic.go

@@ -8,8 +8,8 @@ package cmp
 
 import "reflect"
 
-const supportAllowUnexported = false
+const supportExporters = false
 
 func retrieveUnexportedField(reflect.Value, reflect.StructField) reflect.Value {
-	panic("retrieveUnexportedField is not implemented")
+	panic("no support for forcibly accessing unexported fields")
 }

vendor/github.com/google/go-cmp/cmp/export_unsafe.go

@@ -11,7 +11,7 @@ import (
 	"unsafe"
 )
 
-const supportAllowUnexported = true
+const supportExporters = true
 
 // retrieveUnexportedField uses unsafe to forcibly retrieve any field from
 // a struct such that the value has read-write permissions.
@@ -19,5 +19,7 @@ const supportAllowUnexported = true
 // The parent struct, v, must be addressable, while f must be a StructField
 // describing the field to retrieve.
 func retrieveUnexportedField(v reflect.Value, f reflect.StructField) reflect.Value {
-	return reflect.NewAt(f.Type, unsafe.Pointer(v.UnsafeAddr()+f.Offset)).Elem()
+	// See https://github.com/google/go-cmp/issues/167 for discussion of the
+	// following expression.
+	return reflect.NewAt(f.Type, unsafe.Pointer(uintptr(unsafe.Pointer(v.UnsafeAddr()))+f.Offset)).Elem()
 }

vendor/github.com/google/go-cmp/cmp/options.go

@@ -225,8 +225,20 @@ func (validator) apply(s *state, vx, vy reflect.Value) {
 
 	// Unable to Interface implies unexported field without visibility access.
 	if !vx.CanInterface() || !vy.CanInterface() {
-		const help = "consider using a custom Comparer; if you control the implementation of type, you can also consider AllowUnexported or cmpopts.IgnoreUnexported"
+		const help = "consider using a custom Comparer; if you control the implementation of type, you can also consider using an Exporter, AllowUnexported, or cmpopts.IgnoreUnexported"
-		panic(fmt.Sprintf("cannot handle unexported field: %#v\n%s", s.curPath, help))
+		var name string
+		if t := s.curPath.Index(-2).Type(); t.Name() != "" {
+			// Named type with unexported fields.
+			name = fmt.Sprintf("%q.%v", t.PkgPath(), t.Name()) // e.g., "path/to/package".MyType
+		} else {
+			// Unnamed type with unexported fields. Derive PkgPath from field.
+			var pkgPath string
+			for i := 0; i < t.NumField() && pkgPath == ""; i++ {
+				pkgPath = t.Field(i).PkgPath
+			}
+			name = fmt.Sprintf("%q.(%v)", pkgPath, t.String()) // e.g., "path/to/package".(struct { a int })
+		}
+		panic(fmt.Sprintf("cannot handle unexported field at %#v:\n\t%v\n%s", s.curPath, name, help))
 	}
 
 	panic("not reachable")
@@ -360,9 +372,8 @@ func (cm comparer) String() string {
 	return fmt.Sprintf("Comparer(%s)", function.NameOf(cm.fnc))
 }
 
-// AllowUnexported returns an Option that forcibly allows operations on
+// Exporter returns an Option that specifies whether Equal is allowed to
-// unexported fields in certain structs, which are specified by passing in a
+// introspect into the unexported fields of certain struct types.
-// value of each struct type.
 //
 // Users of this option must understand that comparing on unexported fields
 // from external packages is not safe since changes in the internal
@@ -386,10 +397,24 @@ func (cm comparer) String() string {
 //
 // In other cases, the cmpopts.IgnoreUnexported option can be used to ignore
 // all unexported fields on specified struct types.
-func AllowUnexported(types ...interface{}) Option {
+func Exporter(f func(reflect.Type) bool) Option {
-	if !supportAllowUnexported {
+	if !supportExporters {
-		panic("AllowUnexported is not supported on purego builds, Google App Engine Standard, or GopherJS")
+		panic("Exporter is not supported on purego builds")
 	}
+	return exporter(f)
+}
+
+type exporter func(reflect.Type) bool
+
+func (exporter) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
+	panic("not implemented")
+}
+
+// AllowUnexported returns an Options that allows Equal to forcibly introspect
+// unexported fields of the specified struct types.
+//
+// See Exporter for the proper use of this option.
+func AllowUnexported(types ...interface{}) Option {
 	m := make(map[reflect.Type]bool)
 	for _, typ := range types {
 		t := reflect.TypeOf(typ)
@@ -398,13 +423,7 @@ func AllowUnexported(types ...interface{}) Option {
 		}
 		m[t] = true
 	}
-	return visibleStructs(m)
+	return exporter(func(t reflect.Type) bool { return m[t] })
-}
-
-type visibleStructs map[reflect.Type]bool
-
-func (visibleStructs) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
-	panic("not implemented")
 }
 
 // Result represents the comparison result for a single node and
@@ -436,6 +455,11 @@ func (r Result) ByFunc() bool {
 	return r.flags&reportByFunc != 0
 }
 
+// ByCycle reports whether a reference cycle was detected.
+func (r Result) ByCycle() bool {
+	return r.flags&reportByCycle != 0
+}
+
 type resultFlags uint
 
 const (
@@ -446,6 +470,7 @@ const (
 	reportByIgnore
 	reportByMethod
 	reportByFunc
+	reportByCycle
 )
 
 // Reporter is an Option that can be passed to Equal. When Equal traverses

vendor/github.com/google/go-cmp/cmp/path.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"github.com/google/go-cmp/cmp/internal/value"
 )
 
 // Path is a list of PathSteps describing the sequence of operations to get
@@ -41,7 +43,7 @@ type PathStep interface {
 	// In some cases, one or both may be invalid or have restrictions:
 	//	• For StructField, both are not interface-able if the current field
 	//	is unexported and the struct type is not explicitly permitted by
-	//	AllowUnexported to traverse unexported fields.
+	//	an Exporter to traverse unexported fields.
 	//	• For SliceIndex, one may be invalid if an element is missing from
 	//	either the x or y slice.
 	//	• For MapIndex, one may be invalid if an entry is missing from
@@ -207,6 +209,7 @@ type SliceIndex struct{ *sliceIndex }
 type sliceIndex struct {
 	pathStep
 	xkey, ykey int
+	isSlice    bool // False for reflect.Array
 }
 
 func (si SliceIndex) Type() reflect.Type             { return si.typ }
@@ -301,6 +304,72 @@ func (tf Transform) Func() reflect.Value { return tf.trans.fnc }
 // The == operator can be used to detect the exact option used.
 func (tf Transform) Option() Option { return tf.trans }
 
+// pointerPath represents a dual-stack of pointers encountered when
+// recursively traversing the x and y values. This data structure supports
+// detection of cycles and determining whether the cycles are equal.
+// In Go, cycles can occur via pointers, slices, and maps.
+//
+// The pointerPath uses a map to represent a stack; where descension into a
+// pointer pushes the address onto the stack, and ascension from a pointer
+// pops the address from the stack. Thus, when traversing into a pointer from
+// reflect.Ptr, reflect.Slice element, or reflect.Map, we can detect cycles
+// by checking whether the pointer has already been visited. The cycle detection
+// uses a seperate stack for the x and y values.
+//
+// If a cycle is detected we need to determine whether the two pointers
+// should be considered equal. The definition of equality chosen by Equal
+// requires two graphs to have the same structure. To determine this, both the
+// x and y values must have a cycle where the previous pointers were also
+// encountered together as a pair.
+//
+// Semantically, this is equivalent to augmenting Indirect, SliceIndex, and
+// MapIndex with pointer information for the x and y values.
+// Suppose px and py are two pointers to compare, we then search the
+// Path for whether px was ever encountered in the Path history of x, and
+// similarly so with py. If either side has a cycle, the comparison is only
+// equal if both px and py have a cycle resulting from the same PathStep.
+//
+// Using a map as a stack is more performant as we can perform cycle detection
+// in O(1) instead of O(N) where N is len(Path).
+type pointerPath struct {
+	// mx is keyed by x pointers, where the value is the associated y pointer.
+	mx map[value.Pointer]value.Pointer
+	// my is keyed by y pointers, where the value is the associated x pointer.
+	my map[value.Pointer]value.Pointer
+}
+
+func (p *pointerPath) Init() {
+	p.mx = make(map[value.Pointer]value.Pointer)
+	p.my = make(map[value.Pointer]value.Pointer)
+}
+
+// Push indicates intent to descend into pointers vx and vy where
+// visited reports whether either has been seen before. If visited before,
+// equal reports whether both pointers were encountered together.
+// Pop must be called if and only if the pointers were never visited.
+//
+// The pointers vx and vy must be a reflect.Ptr, reflect.Slice, or reflect.Map
+// and be non-nil.
+func (p pointerPath) Push(vx, vy reflect.Value) (equal, visited bool) {
+	px := value.PointerOf(vx)
+	py := value.PointerOf(vy)
+	_, ok1 := p.mx[px]
+	_, ok2 := p.my[py]
+	if ok1 || ok2 {
+		equal = p.mx[px] == py && p.my[py] == px // Pointers paired together
+		return equal, true
+	}
+	p.mx[px] = py
+	p.my[py] = px
+	return false, false
+}
+
+// Pop ascends from pointers vx and vy.
+func (p pointerPath) Pop(vx, vy reflect.Value) {
+	delete(p.mx, value.PointerOf(vx))
+	delete(p.my, value.PointerOf(vy))
+}
+
 // isExported reports whether the identifier is exported.
 func isExported(id string) bool {
 	r, _ := utf8.DecodeRuneInString(id)

vendor/github.com/google/go-cmp/cmp/report_compare.go

@@ -81,14 +81,19 @@ func (opts formatOptions) FormatDiff(v *valueNode) textNode {
 		return opts.FormatDiffSlice(v)
 	}
 
+	var withinSlice bool
+	if v.parent != nil && (v.parent.Type.Kind() == reflect.Slice || v.parent.Type.Kind() == reflect.Array) {
+		withinSlice = true
+	}
+
 	// For leaf nodes, format the value based on the reflect.Values alone.
 	if v.MaxDepth == 0 {
 		switch opts.DiffMode {
 		case diffUnknown, diffIdentical:
 			// Format Equal.
 			if v.NumDiff == 0 {
-				outx := opts.FormatValue(v.ValueX, visitedPointers{})
+				outx := opts.FormatValue(v.ValueX, withinSlice, visitedPointers{})
-				outy := opts.FormatValue(v.ValueY, visitedPointers{})
+				outy := opts.FormatValue(v.ValueY, withinSlice, visitedPointers{})
 				if v.NumIgnored > 0 && v.NumSame == 0 {
 					return textEllipsis
 				} else if outx.Len() < outy.Len() {
@@ -101,8 +106,8 @@ func (opts formatOptions) FormatDiff(v *valueNode) textNode {
 			// Format unequal.
 			assert(opts.DiffMode == diffUnknown)
 			var list textList
-			outx := opts.WithTypeMode(elideType).FormatValue(v.ValueX, visitedPointers{})
+			outx := opts.WithTypeMode(elideType).FormatValue(v.ValueX, withinSlice, visitedPointers{})
-			outy := opts.WithTypeMode(elideType).FormatValue(v.ValueY, visitedPointers{})
+			outy := opts.WithTypeMode(elideType).FormatValue(v.ValueY, withinSlice, visitedPointers{})
 			if outx != nil {
 				list = append(list, textRecord{Diff: '-', Value: outx})
 			}
@@ -111,9 +116,9 @@ func (opts formatOptions) FormatDiff(v *valueNode) textNode {
 			}
 			return opts.WithTypeMode(emitType).FormatType(v.Type, list)
 		case diffRemoved:
-			return opts.FormatValue(v.ValueX, visitedPointers{})
+			return opts.FormatValue(v.ValueX, withinSlice, visitedPointers{})
 		case diffInserted:
-			return opts.FormatValue(v.ValueY, visitedPointers{})
+			return opts.FormatValue(v.ValueY, withinSlice, visitedPointers{})
 		default:
 			panic("invalid diff mode")
 		}

vendor/github.com/google/go-cmp/cmp/report_reflect.go

@@ -74,7 +74,7 @@ func (opts formatOptions) FormatType(t reflect.Type, s textNode) textNode {
 
 // FormatValue prints the reflect.Value, taking extra care to avoid descending
 // into pointers already in m. As pointers are visited, m is also updated.
-func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out textNode) {
+func (opts formatOptions) FormatValue(v reflect.Value, withinSlice bool, m visitedPointers) (out textNode) {
 	if !v.IsValid() {
 		return nil
 	}
@@ -108,12 +108,15 @@ func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out t
 		return textLine(fmt.Sprint(v.Bool()))
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		return textLine(fmt.Sprint(v.Int()))
-	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+	case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-		// Unnamed uints are usually bytes or words, so use hexadecimal.
+		return textLine(fmt.Sprint(v.Uint()))
-		if t.PkgPath() == "" || t.Kind() == reflect.Uintptr {
+	case reflect.Uint8:
+		if withinSlice {
 			return textLine(formatHex(v.Uint()))
 		}
 		return textLine(fmt.Sprint(v.Uint()))
+	case reflect.Uintptr:
+		return textLine(formatHex(v.Uint()))
 	case reflect.Float32, reflect.Float64:
 		return textLine(fmt.Sprint(v.Float()))
 	case reflect.Complex64, reflect.Complex128:
@@ -129,7 +132,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out t
 			if value.IsZero(vv) {
 				continue // Elide fields with zero values
 			}
-			s := opts.WithTypeMode(autoType).FormatValue(vv, m)
+			s := opts.WithTypeMode(autoType).FormatValue(vv, false, m)
 			list = append(list, textRecord{Key: t.Field(i).Name, Value: s})
 		}
 		return textWrap{"{", list, "}"}
@@ -156,7 +159,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out t
 					continue
 				}
 			}
-			s := opts.WithTypeMode(elideType).FormatValue(vi, m)
+			s := opts.WithTypeMode(elideType).FormatValue(vi, true, m)
 			list = append(list, textRecord{Value: s})
 		}
 		return textWrap{ptr + "{", list, "}"}
@@ -171,7 +174,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out t
 		var list textList
 		for _, k := range value.SortKeys(v.MapKeys()) {
 			sk := formatMapKey(k)
-			sv := opts.WithTypeMode(elideType).FormatValue(v.MapIndex(k), m)
+			sv := opts.WithTypeMode(elideType).FormatValue(v.MapIndex(k), false, m)
 			list = append(list, textRecord{Key: sk, Value: sv})
 		}
 		if opts.PrintAddresses {
@@ -189,7 +192,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out t
 			ptr = formatPointer(v)
 		}
 		skipType = true // Let the underlying value print the type instead
-		return textWrap{"&" + ptr, opts.FormatValue(v.Elem(), m), ""}
+		return textWrap{"&" + ptr, opts.FormatValue(v.Elem(), false, m), ""}
 	case reflect.Interface:
 		if v.IsNil() {
 			return textNil
@@ -197,7 +200,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, m visitedPointers) (out t
 		// Interfaces accept different concrete types,
 		// so configure the underlying value to explicitly print the type.
 		skipType = true // Print the concrete type instead
-		return opts.WithTypeMode(emitType).FormatValue(v.Elem(), m)
+		return opts.WithTypeMode(emitType).FormatValue(v.Elem(), false, m)
 	default:
 		panic(fmt.Sprintf("%v kind not handled", v.Kind()))
 	}
@@ -209,7 +212,7 @@ func formatMapKey(v reflect.Value) string {
 	var opts formatOptions
 	opts.TypeMode = elideType
 	opts.ShallowPointers = true
-	s := opts.FormatValue(v, visitedPointers{}).String()
+	s := opts.FormatValue(v, false, visitedPointers{}).String()
 	return strings.TrimSpace(s)
 }
 

vendor/github.com/google/go-cmp/cmp/report_slices.go

@@ -172,7 +172,9 @@ func (opts formatOptions) FormatDiffSlice(v *valueNode) textNode {
 					switch t.Elem().Kind() {
 					case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 						ss = append(ss, fmt.Sprint(v.Index(i).Int()))
-					case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+					case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+						ss = append(ss, fmt.Sprint(v.Index(i).Uint()))
+					case reflect.Uint8, reflect.Uintptr:
 						ss = append(ss, formatHex(v.Index(i).Uint()))
 					case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
 						ss = append(ss, fmt.Sprint(v.Index(i).Interface()))

vendor/modules.txt

@@ -1,4 +1,5 @@
-# github.com/google/go-cmp v0.3.1
+# github.com/google/go-cmp v0.4.1
+## explicit
 github.com/google/go-cmp/cmp
 github.com/google/go-cmp/cmp/internal/diff
 github.com/google/go-cmp/cmp/internal/flags